Purpose:
To determine the potential of SLP in acute NAION for correlating with presenting visual field loss and predicting the field and retinal nerve fiber loss outcomes.
Methods:
25 eyes with NAION (mean duration of vision loss 9 days at presentation) were tested with automated perimetry, SLP and OCT at baseline, 1 month and at 6 months. SLP and OCT average RNFL values for the superior and inferior arcuate regions, derived from Garway-Heath RNFL mapping, were compared to their corresponding inferior and superior visual field sensitivity.
Results:
At presentation, average SLP superior (51+16µm) and inferior (54 +9.6µm) regions were significantly worse in eyes with loss in corresponding field regions compared to eyes with normal field regions (superior 69 +4.7µm; inferior 73 +16.6µm). A significant linear relationship between SLP derived RNFL thickness and visual field sensitivity was found at baseline (r=0.32) and at 1 month (correlation r=0.55) following acute NAION. In contrast, OCT derived RNFL thickness showed no significant relationship during the same time periods when the optic nerve was still swollen. A linear correlation was found between baseline SLP derived RNFL during acute NAION and the > 6 month OCT RNFL (r=0.29).
Conclusions:
SLP derived RNFL reduction is frequent in arcuate regions corresponding to visual field loss at presentation in eyes with acute NAION, when OCT derived RNFL shows increases from edema. SLP derived RNFL decrease seems to be an early marker for injury and permanent field and RNFL loss, while normal RNFL derived from SLP might occur in regions with potential for recovery.
Keywords: optic nerve • imaging/image analysis: clinical • neuro-ophthalmology: optic nerve